Carrier transport and bias stress stability of IGZO TFT with heterojunction channel

An InGaZnOx (IGZO) thin-film transistor (TFT) has been received considerable attention for use in next-generation displays owing to their excellent electrical properties. Although a field effect mobility (mFE) of the IGZO TFT (10~15 cm2V–1s–1) is over ten times larger than that of an amorphous silicon TFT, further enhancement of the mFE is desired to expand their applications. Several approaches have been proposed to improve the mFE of oxide TFT. Among them, it is known in the IGZO material system that an increase of In content is effective to enhance the mFE of the IGZO TFT since a conduction band of the IGZO is mainly composed of an In 5s orbitals. However, high In composition leads to an increase carrier concentration (oxygen vacancy) in the film, result in a degradation of TFT properties such as negative shift of threshold voltage and hump in transfer characteristics. Please click Additional Files below to see the full abstract